Artificial arm



June 19, 1923. 1,458,923

D. M. ANDERSON ARTIFICIAL ARM Filed June 5, 1922 wrn.

Patented June 19, 1923.

DUNCAN, MACKENZIE ANnERs0N',..or MAIN'Z, GERMANY.

ARTIFICIAL ARM...

' Application filed June 3,

To all whom it may concern:

Bevit known that. I, DUNCAN MACKENZIE ANDERSON, a citizen of Canada,residing'at' Mainz, Germany, have invented certain new and usefulImprovements in Artificial Arms, ofwhich the following is aspecification.

To produce the movement of the forearm of an artificial arm attached toa stump of the upper arm by traction means connected with the forearmand with a fixed point of the human body and conducted over inter-.

posed reversin elements, has become known already. The ending positionof the upper arm is produced. with devices of thistype by the stump.

This invention relates to an improvement of artificialarms of this typein such a sense, that thetransformation of the lifting movement of theshoulder into the lifting move-- ment of the artificial arm is effected,with exclusion of elements. situated outside the artificial arm exceptthepoints of attach-' ment to the human body, from points which are-allsituated in the artificial arm, and enclosed and hidden by the same,-the ele ments for changing the direction of I the traction element beingsupported in *the shoulder joint of the artificialarm, whereby furtherthe angular torsion of the guiding elements in the shoulder joint, whichoccurs at the lifting of the shoulder, is transferred at first only uponthe joint of the forearm to produce the bent position of the forearm tobe transferredonly hereafter for producing the lifting of the wholear'm.. Owing to the suppression of reversing elements for the pull ropearranged outside the artificial arm, the attachment and the carrying ofthe artificial arm is facilitated and rendered morecomfortable, its use.is

less exposed to disturbances and the elements for transmitting andexecuting the movements are well protected inthe artificial arm. Theincrease. of weight is of little importance as the principal mass of thereversing elements is situated in the shoulder joint and has to be drawnalong only very little at the lifting of the arm.

An embodiment of the invention is shown on the accompanying drawing,wherein 5-- Fig. 1 is a diagram illustrating the idea of the invention.

Fig. 2 isa front elevation, the artificial arm being shown cut open.

Fig. 3 is a side elevation viewed from the left, the artificial armbeing omitted.

1922. Serial No. 565,760.

If to the human body and upon'the cor- I respondingshoulder, with theaid of a bandage 1, an artificialv armis'attach'ed"whose upper arm 2 isarticulated to the bandage by a pivot pin'and whose forearm isarticulated in the well known manner to the up-- per'arm, andif' furtherfrom a fixed point 4: of the human body a pull rope 5 isguided over; apulley 6 pivotally mounted in'the shoulder joint where theend ofsaidrope is made fast after having been wound partly or completelyaround said pulley, in. y order that the rope with the pulley can 6X8cutean angular rotation, and. if a second pulley 7 rigidly coupled withthe first mentioned pulley is connected in the same manner but ininverse succession by a pull rope 8 with the artificial;forearm, thepulleys 6 and .7 can executean'angular rotation if the shoulder .withthe artificial arm is lifted, OWlIlgtO the lengthening of the distancebetween theffixed point a and the joint of the shoulder, the artificialforearm and later, on thewhole arm being thus able to execute a bendingmovement ill-the direction of the arrow. At the loweringof theshoulderthe initial position is resumed by the action of the naturalweight or with the aid of springs.

This is'the principle upon'which' the form of. construction shown inFigures 2 and 3 is-based'. Y

The artificial armis attached to the body in the Well known manner bystraps which terminate at the shoulder joint in a leather sleeve orhaving a metal bow b withthe trav erse 0 serving as'bearing. Thistravel-sec forms together with thefrontend of the journald;theQsho-ulder oint. Upon the rear part of the journal (Z the: pulleys e,f for changing the direction of the ropes are 1 mounted which arerigidly connected the one with the other. Uponthefront parti of thejournal 03' a joint cross is mounted which embracesa connecting rod hfrom: both sides. The artificial upper arm z is connected with the frontends of the cross 9 (Fig.

2). The artificial upper arm 11 is open at the upper end and covered bya leather cap is (Fig. 3). Parallel rods Zhinged tothe cross 9 aremounted at their lower ends each by an eye upon the pivotpin n. Thejointcross 9 has further two parallel arms 9" which are bent at aconvenient angle and have each an angularly bent slot 0. Be-

tween the arms 9 an arm 72, of the con-,

necting rod 71. is located which has laterally projecting studs pengaging with. the slots 0. The connecting rod it has a verticallongitudinal slot Q traversed by the journal cl and by an upper stud 7"supported by the traverse c. The connecting rod h is hinged by anarticulation t to a rod 14 which has a longitudinal slot 1) guided uponthe bolt 72. To this bolt n the artificial forearm i is attached bymeans of lug-straps 'w, the forearm being. united with the artificialupper arm by a ball joint the pivot pin of which is formed by bolt n.Upon'the bolt n inclined arms :0 arranged in pairs are fixed which havelongitudinal slots at and enclose a lug; u. of the rod a, which engagesby a bolt y withthe longitudinal slots 00. Upon the bolt 1 a rod 2 isfurther mounted by its lug, said rod being extended by a chain 2 guideduponthe pulley f and fixed to the crown of the same. The pull rope jattached with one end at a convenient point of the: body is guided overthe pulley e and attached with its other end in the groove of thepulleyafter it has been wound around part of the pulley. 1

If the shoulder is lifted the pulley is revolved by the pull rope ofacorresponding angle. The pulley f participates in this revolvingmovement so that the chain .2 is wound upon the pulley f whereby the rod2 is lifted in the direction of the arrow 1. Herefrom results that thearms 00' are also turned upward in the direction of the arrow IT wherebythe pivot bolt n and consequently the artificial forearm are turned inthe direction of arrow 111. As the rod is however also connected withthe connecting rod u and as this rod is hingedly connected with rod 72these rods are lifted in linear direction (arrow IV). This movement hasat first no consequences until the stud p enters the inclined part ofthe slot 0. At this'moment the automatic lifting movement of the forearmis terminated. The stud p which continues to move in the same directionwill now make the arm 9' turn in the direction of arrow V and. with itthe cross g or the artificial upper arm attached to the same.- Thisartificial upper arm is however lifted by the rods Z connected with thecross 9' which. cause, owing to their connection with the pivot bolt a,the simultaneous oscillation of the forearm and of the upper arm in thedirection of arrow VI.

the direction to the forearm and adapted to be put under tension by thelifting of the shoulder" the combination of a. pull rope made fast withone end to a fixed point of the body and withthe other end to the forearm, with pulleys having their. geometrical axes of rotation coincidingwith the axis of rotation of the artificial shoulder joint,.and

means for stopping this bending; movement.

2. An artificial: arm of'the type described and shown comprising incombination with a pull rope attached with one end to a: fixed point ofthe human'body and with the other end to the forearm, a large ropepulley, and

a small rope pulley, the axle upon which said rope pulleys are mountedsituated in the axis of articulation of the shoulder joint, a straightguide for the pull rope, a pivot bolt for the forearm, a pair ofarmsconnected' with said pivot bolthaving slots and designed to; transferthe angular rotation of the rope pulleys to theforearm for making thesame oscillate, a jointedcrossmounted. upon said axle of the shoulderjoint, a slotted arm of said joint cross, a linear guide link upwardlyextending from the pivot bolt of the forearm, an arm of said linearguide link, a stud projecting from said arm engaging with'said slottedarm of the joint cross so that the joint cross is partly revolved, androds rigidly connecting said joint cross with said pivot bolt fortransferring the part rotation of the joint cross to the artificialforearm for'oscillating' the same together with the artificial upperELI'IH.

In testimony whereof I affix my signature in presence of two witnesses.

' DUNCAN" MACKENZIE ANDERSON; Witnesses:

H. Bnonnw, EMILE BLOUIN'.

I lit)

